Magnetic speed-indicator



(No Mode'Ly E. WESTON.

MAGNBTIG SPEE'D INDICATOR;

Nd. 277,179. Patented May 8,1883.

This fact I have taken advantage of in conspindle I fix a pulley or some other means for tion of the disk undervolving magnet is indicated by the pointer. .I

Fig. 2, a central vertical section of the axisof the disks. tendency to rotate in the *device being substantially a disk of metal, preferably copper, upon a spin- .mal position of rest, is distended, or wound up UNITED STATES 'ATEN'F" OFFER? EDWARD-QWESTON, or NEWARK, NEW JERSEY.

' MAGNETIC} spasm-momm es.

srn'czrrca'rzo'n forming part of Letters Patent No. 277,179, dated m 3, 1883.

Appliontion-hled January i9, 1883. (No model.)

To all whom itmayconcem: r Be, it .known that I, EDWARD Wnsroma subject ofthe Queen ot'tireatBritaimand a resident of Ne'wark,in the county of Essex-and State of New Jersey, have invented certain new and useful Improvements in lllagnetic speeddudicators, of which the following is a specification, reference being had to the draw ings accompanying 'and forminga part of the same; i i It is well known thatif one or both poles of a magnet be held in face of a metal disk mounted so asto rotate freely and revolved about same direction as the magnet is imparted to the disk. This tendency is due to a certain drag or pull exercised by the poles upon the disk, and is proportionai, or practicallyso, to the speed of revolution of the poles, assuming that their magnetic stre ll remains the same.

structing a device for indicating the speed of shafts, or of rotating bodies generally, the principle of construction and operation of suchas follows: I mount dle which carries a suitable pointer. With the disk is connected a spring or. equivalent device, w hich,'as"th disk is turned from its'noras the case may be. In face of the disk mount on a spindle a short magnet, either a permanent or an electro magnet, and upon the imparting to it a speed of rotation correspond. ing to that of the shaft or body the speed of The rotation of the magnet imparts to the disk a tendency to turn against the forceof the spring connected with'i-t, and as this tendency is always the same for a given-rate of speed it may be taken as a measure of the speed. The posithe influence of the re have in the drawingsshown a simple and practicable application of this principle that speedindicator for shafts, and I will 'now describe the same by reference to the 'figures. V

Figure 1 is a face view of the instrument;

' in all the figures.

the same;

disk, showing section Fig. 4, a view of the Fig. 3, a plan view of the metal its spindle in magnet.

Similar letters indicate corresponding parts I The letterA designates a cylindrical casing with front and rear plates, B 0. Upon the face of the-front plate, B,-is cut or pasted a scale inclosed by a glass plate, I), which is retained in place by a bezel, E. To the inner face of plate B is fixeda metal block or sleeve, b, through which passes a spindle. a, carrying a pointer, p, that'sweepsover the scale. To the inner end of spindle c is fixed acopper disk, F. S is a spiral spring, the ends of which are made fast to the slccveb and to the disk F, respectively, so that the disk, when turned, increases the tension of the spring. A stop, 0, upon the face'of plate B limits the backward movement of the disk F and pointer 9.

To the inner face'of the rear plate, U, issecured a sleeve, 11,, serving as a bearing for a spindle, e. To the outer end of this spindle is fixed a pulley-wheel, G,'or it may be a fric-- tion-disk or other equivalent device, for cou heating the spindle'with a rotating body. To the inner end of spindle e istixed a short has magnet, M. It may-beestated that this magnet may be of softirou and wound with a coil of insulated wire, through which a definite amount of current may be passed in many well-understood ways when the apparatus is H] use. When the pulley-wheel G or its equivalent is imparted to the magnet M pulls the disk F around against the force of spring 8.; The pointer is thus movedov'er the scale and indicates the force exercised upon the disk by the magnet, and therefore the speed at which the magnet-is rotating. By a simple series of experimcnts the scale may he laid ott' for varying speeds, so that the position of the pointer will indicate the numherot revolutions per unit of timeot' the spindle e orthe shaft with which it is connected.

It is evident that the mechanical construction of the apparatus may be greatly variedas, for instance, the pointer or other means for connected with a rotating shaft the motion other corresponding to snchposition, as set forth.

the magnet the disk;

3. The comhinationof two spindles, a point- :5 er, and metal disk secured to one, a magnet and pulley or its equivalent secured to the other, and a springconnected with the disk or its spindle andto a fixed object, these parts ous conductor similar to a disk may be used being'constrnct'ed and arranged in such manin its stead. ner that a. rotary movementimparted to the W'hat I claim is- V Y magnet may partially turn the metal disk, as

l. The combination of a. magnet and a conand for the purpose set forth. tinuonsconductor mounted or arranged sothat 4. The dombination, with' box A and front the rotation of one induces a tendency tojroand rear plates, B (l, of the spindles cc, pointer tate in the other, a spring or similar means for secured to spindle c, and magp, and disk I", preventing the free rotationof one, and means, net M and pulley G, secured to spindle 8, these substantially as described. for indicating parts being constructed ill-substantially the changes in its position and the speed of the indicating the speed may he connected with the magnet and the disk revolved byt-he rotating shaft, for it is well'known that the disk may be caused tomeve the magnet as well as also, that any continumanner set forth.

' In testimony whereof I have hereunto seto t Y my hand this 17th day of January, 1883.

2. Thecombinatiomwithaspindle a pointer, p 7 adds metal disk, and a spring for preventing ED WARD WESTON. the 'free rotation of the disk, ofa magnet capahle of being caused to revolve in face of the Witnesses:. disk in such, manner that the disk will he RAYMOND F. BARNES, moved in proportion to the speed of revolution W. FRISBY.

of the magnet, as and fertile purpose set forth. 

